1. Field of the Invention
The present invention relates to a water filter device, and more specially, to a filter having an automatic control of flow.
2. Description of the Prior Art
With the improvement of the quality of life, people are paying more attention to drinking water safety, so that water filters are widely used in daily life.
Principle of filtration is flowing raw water through filter materials to catch impurities so as to obtain drinking water. The filter materials will lose effectiveness after a predetermined quantity of raw water pass through (that is, at the time that maximum rated amount of treated water is reached). Serious secondary pollution will be caused if the raw water is treated by lapsed filter materials and therefore user's safety will be at risk. Accordingly, how to remind users to replace the filter materials in time has became a hotspot in this field.
Most of current filters fail to remind users to replace the filter materials in time due to absence of reminders. However, filters that have reminders require high cost to produce and electric power to maintain operation.
Therefore, we need a new kind of filter having a simpler structure and lower manufacturing costs, which can avoid safety risks by reminding users to replace the filter materials at the time when filter materials fail.